This invention relates generally to door locks and, more particularly, to an improved door lock for a door handle.
A common problem associated with the security of door locks contained within door handles, especially those in hotels or the like, is that they can be opened by a master key. Moreover, such a door lock can often be forced open by turning the door handle with sufficient force to break the lock. A related problem associated with such door locks, especially those in apartments or other premises which may be rented, is that persons other than the owner (e.g., tenants) may have keys to open the lock. Occasions may arise where the owner of the premises wishes to prevent persons who may have keys from entering the premises. In such situations, the owner is ordinarily required to replace all of the door locks which such persons may be able to open. Even if the owner goes to the effort and expense of replacing the door locks, the person who is denied access to the premises may attempt to force open the door lock by turning the door handle with sufficient force to break the lock. Devices heretofore made in an attempt to thwart these methods of opening such door locks are difficult to lock to a door handle, thus making their use, especially by the general public, impractical. There is, therefore, a need for a door lock for a door handle which is easy to use, and prevents insertion of a key into the keyhole and turning of the door handle.
Reference may be made to U.S. Pat. Nos. 3,952,564 and 4,570,470 disclosing devices generally in the field of this invention. It will be noted, however, that locking such devices to a door handle is difficult due to the complicated locking mechanisms and other features.